Method of producing proteinaceous adhesives and the product thereof



United States Patent O METHOD OF PRODUCING PROTEINACEOUS AD- HESIV ES AND THE PRODUCT THEREOF David H. Read, Seattle, Wash., assignor to American- ?l {arietta Company, Seattle, Wash., a corporation of .No Drawing. Application February 16, 1953,

Serial No. 337,209 r 18 Claims. (Cl. 106-435) This invention relates to animproved method of producing proteinaceous adhesives and the product thereof a and more particularly is concerned with the treatment of blood-soy adhesives to improve their spreading capacity and for other advantages.

Glues formed of aqueous alkaline dispersons of blood andsoy flour mixtures have long been usedin the plywood industry. Some of these glues are outstanding in their spreading characteristics but such spreading characteristics largely depend upon the ability of the glue to form a gel. viscosity properties of the glue is one of the most important of all attendant requirements.

Blood-soy mixtures for gluing purposes by comparison with the non-blood containing glues under certain circumstances have very desirable attributes such, for exam ple, as improved spreading, hence better water resistance characteristics; less penetration of the adhesive materials into fibrous materials; the capability of being used in hot presses which includes a gain in moisture resistance due to gelling under heat and pressure; and improved fungus resistance even though no fungicide is employed.

While this invention is widely useful its application in the veneering and plywood industry will be referred to as a particular application.

It is important in current plywood production to impart fungicidal characteristics to a glue line to reduce or prevent mold formation'and consequent deterioration of the plywood. Most protein glues are subjected to the attack of fungi but in the case of soy flour glues the available fungicides are operable and useful and do not particularly interfere or alter the viscosity or spreading characteristics of the glue. Such fungicides usually used are.

chlorinated phenols of which pentachlorophenol is a specific example. Such fungicides are normally employed at the rate of approximately 5% of the dry weight of the proteinaceous ingredients. However when such fungicides are added to a blood base glue, which ordinarily gels, the glue will no longer gel and it will have very inferior and undesirable spreading characteristics. By reason of my invention, set forth more fully herein, I make it possible to include a normal amount of pentachlorm phenol or other chlorinated phenol without loss of the gelling property and at the same time maintain and retain all of the inherent advantages of blood-containing glues.

In order that a blood glue will perform its functions properly, it is essential that it has certain properties or characteristics that these be maintained in proper balance in the glue mixing operation, throughout the spreading operation, during the set-up period, and during the pressing period, as in the case of plywood production. One important property required of the glue is its thixotropy or the ability to forma gel upon standing and yet readily revert to an appropriate fluid state upon controlled conditions of agitation and shear. This property is importantin order that a desired glue spread be obtained with It might be said that the control of the 2,813,037 Patented Nov. 12, 1957 ICC - conventional glue-applying apparatuses as well as the for use in plywood mills is prepared in the usual manner rial for plywood use.

and fungicide of the polychlorophenolic nature is added to the prepared glue an immediate and highly undesirable loss of viscosity of the glue occurs. This loss of viscosity is so deleterious as to practically destroy the glue mate- One particular deleterious effect with low viscosity glues is extreme penetration of the wood fiber and a starvation of the glue line to such'an extent that no desirable bonding results.

I have discovered that the salts of cobalt have a very definite and desirable gel forming capability in aqueous alkaline dispersions of blood and soy flour. This gelation is useful in controlling the viscosity of soy-blood adhesive mixtures and is found particularly useful in those mixes which are treated with a fungicidal material as above mentioned. In both instances, such gelling agent is use ful to avoid loss of spreading properties, thus preventing an undesirably low concentration of adhesive solidsr The method of treating aqueous alkaline adhesive dispersions of soluble blood and soy flour according to the u present invention, in general, comprises treating the dispersion with a gel-forming solution capable in alkaline solution of producing cobalt ions which is, in eifect the production of cobalt hydroxide. A viscosity increase in the dispersion is apparent from the time of the addition of the cobalt material and progresses upward with the mixture.

passage of time. The gel-forming material may be either cobalt chloride or cobalt sulfate or a mixture of the same.

The treating may be carried out shortly after the completion of the mixing of the proteinaceous ingredients and this type has previously caused a troublesome loss of viscosity, infact the adhesive never attains a gel structure. This defect has previously prevented use of these fungiicides with such blood soy glues. objects of this invention has been to overcome this difliculty and to do so in a simple direct and entirely practical manner. 1

In the preferred form of the invention, a base glue material comprising blood and soy proteinaceous materials in the ratio of 2:3 blood to soy is added to water, preferably at room temperature, followed by mixing for 5 min utes. Thereafter a substantial quantity of Water is added,

and following a short mix, lime slurry is introducedand mixed for about 1 minute whereupon a sodium hydroxide solution is added and mixed. To this mixture are introduced silicate of soda and carbon tetrachloride, followed One of the primary This last addition is designed and included to prevent loss of viscosity and spreading characteristics which would otherwise result upon the addition of the fungicide. Then sodium pentachlorophenate in an amount approximating 5% by weight of .the blood-soy mixture is added. This procedure produces a glue highly suitable for spreading onfir plywood cores at a rate of 78 lbs. of glue per 1000 ft. of core stock as used in inch panels.

-In arriving atmy invention I first considered the use of several metallic salts as being materials potentially capable of producing gelation in alkaline dispersions of bloodsoy flour. The following example sets forth the results of my investigation with nickel, iron and cobalt salts.

Exarnple 1 #26 Wire High-Shear Additive McMichael Viscosity Ratio Viscosity Cobaltous sulfate heptahydrate 390 4. 75 87 Ferrous sulfate (anhydrous) 6O 3. 5 17 N iekelous sulfate hexahydrate- 47 3. 5 13 No additive 54 3. 7 14 The high shear viscosity test mentioned above is made as follows: the viscous material to be tested is placed in a spring-biased sample cup mounted in suitable upright bearings to rotate freely, a weight bob or'plug having an upstanding stem and loosely fitting within said cup is placed in the cup over the test sample and pressed down until material rises to the upper face of the bob which is then rotated at a speed at 1300 R. P. M. whereupon torque is applied to the freely rotatable cup and readings may be taken thereof from an outstanding torque radius arm in relation to a calibrated scale.

From the foregoing it will be apparent that, with a proteinaceous material having a McMichael #26 wire) viscosity that is quite low, neither the ferrous sulfate nor the nickelous sulfate had a material effect in a favorable direction upon viscosity. On the other hand an extremely high viscosity was obtained in the instance where cobalt sulfate was employed.

This work indicates a surprising and unexpected difference between cobalt and the other metallic salts in promoting gelation. A large number of other salts were used in various other investigations but without beneficial resutls. It was later determined as will be set forth more fully that the alum had no appreciable effect upon viscosity.

In order to determine in a practical manner whether or not the cobalt salt would be effective under actual gluemixing and veneer-spreading conditions in the plywood industry, the following example was carried out:

Example 2 The following glue mix was prepared in a plywood mill and was used in the regular mill equipment for gluing plywood.

200 lbs. water 170 lbs. soy-blood glue (where blood was 34% by weight of the dry mix ingredients). Mix 5 minutes 495 lbs. water. Mix 1 minute 33 lbs. lime slurry (33%). Mix 1 minute 28 lbs. caustic (50%). Mix 1 minute 60 lbs. silicate of soda (N grade). Mix 1 minute 5 lbs. carbon-tetrachloride. Mix 2 minutes /2 lb. cobaltous chloride (heptahydrate) in 16 lbs. water.

-Mix 1 minute 42 lbs. of sodium pentachlorophenate solution (20%) (5% by weight of dry glue mix). Mix 5 minutes.

The foregoing glue was spread on plywood cores at the rate of 78 lbs. per 1000 feet of double glueline, that is approximately 39 lbs. of glue was spread for each glueline and 3-ply panels (final thickness 7 inch) were assembled and pressed in a hot press at 225 F. for 2 minutes at approximately 180 p. s. i. From typical panels of such production three 6-inch squares of material were cut from each of four panels. These were tested by the method prescribed for this type of glue, namely; 5 cycles of alternate soaking in water and drying. This is a standard test procedure for interior grades of plywood. All tested material survived these tests without sustaining any delamination.

It was considered desirable to make a further study of the action 'of cobalt ions on blood and soy flour materials to determine on which the cobalt solution was the most effective. Thereupon the following investigation was made:

Example 3 A comparison between the action of cobalt ion on blood and on soy flour. Sample 1, consists of 50 grams of soluble blood mixed with 240 grams of water and about one gram of antifoam; 27 grams of 33% caustic and 5 grams of Water are added. Sample 2, contains the same ingredients, with the addition of 0.3 gram of cobalt chloride in the last 5 grams of water. Sample 3, consists of 75 grams of soy flour in 250 grams of water with about one gram of antifoam. Sample 4, resembles 3, except for the addition of 0.3 gram of cobalt chloride in the last 5 grams of water. The McMichael viscosity of each sample was determined six minutes after the last addition.

Viscosity 180 315 42 Though the gelling power of cobalt ion with blood is much stronger than with soy flour, the latter is spectacularly affected by larger amounts. If the equivalent of four times as much cobalt chloride is added to 75 grams of soy flour suspension (as above), the viscosity under the same conditions rises to 310.

It is believed csablished that any material which furnishes sufiicient cobalt ion when added to an aqueous alkaline solution is capable of acting as a gelling agent with blood-soy flour glue mixes. As the cobalt salt dissolves, the viscosity of the solution arises.

Further experimentation in the matter was as follows:

Example 4 A laboratory-size mix using the same ratio of ingredients as in Example 2 preceeding, had a viscosity of 205 (McMichael) after standing one hour. A mix similar to the above except for substitution of 1.2 parts of cobalt sulfate heptahydrate for each part of cobalt chloride hexahydrate has a viscosity of 235 (McMichael).

The cobalt salts are added in aqueous solution to avoid lumping and facilitate dispersion of the cobalt ion throughout the adhesive mixture. The amount of cobalt-containing material maybe varied if desired in order to thicken orthin the glue. For a glue of the type shown in Example 2, the usual practical limits will be from to pound of cobaltous chloride, to maintain the desired glue viscosity. The viscosity is also materially affected by changes'in the time of adding cobalt.

The curve of viscosity versus time displayed by normal blood-soy adhesives of the type herein described shows a sharp initial increase in viscosity and a subsequent level 11 of 33% caustic and 5 grams of water are added.

portion which decreases slowly as the glue ages. In order to obtain such a curve with an adhesive to which cobalt salts and pentachlorophenol have been added, as in Example 2, the time at which these latter ingredients are added is very critical. If they are added too soon after the other chemical additives, or too late, the shape of the viscosity curve will be distorted and the usefulness of the adhesive will be impaired.

The above specific examples are merely illustrative of the invention and numerous modifications will be appar ent to those skilled in the art. For example, the fungicide material may be added in the solid form or even as the free pentachlorophenol. Likewise other polychlorophenols may be used, however considerations bearing on the matter stated above must be taken into account in such variations.

The methods described in Example 2 are merely those preferred in practicing the invention with the specific ingredients used in that example.

Having thus described my invention, I claim:

1. In an aqueous alkaline adhesive dispersion of a finely divided proteinaceous adhesive material consisting essentially of soluble dried blood and soya flour in a ratio of from 2:3.7 to 4: 1, containing a viscosity decreasing fungicide in an amount equivalent to about 5% by weight of the'dry proteinaceous material, a cobalt salt soluble in the mixture producing a concentration of cobalt ions raising the viscosity of the adhesive at least as much as it is decreased by the fungicide.

2. The subject matter of claim 1 in which the ratio of soluble blood to soya flour is approximately 2:3.7 and the cobalt salt is present in an amount equivalent to about 0.25% by weight of the dry proteinaceous material.

3. The subject matter of claim 1 in which said cobalt salt is cobaltous chloride.

4. The subject matter of claim 1 in which the cobalt salt is cobaltous sulfate.

5. In an aqueous alkaline adhesive dispersion of a finely divided proteinaceous adhesive material consisting essentially of soluble dried blood and soya flour in a ratio of from 2:3.7 to 4:1, containing a chlorinated phenol fungicide in an amount equivalent to about 5% by weight of the dry proteinaceous material, said chlorinated phenol reducing the viscosity of the said adhesive, a cobalt salt in an amount equivalent to about 0.1% to about 0.5% by weight of the dry proteinaceous material where the cobalt salt is calculated on the anhydrous basis, said salt being soluble in the mixture producing a concentration of cobalt ions raising the viscosity of the adhesive at least as much as it is decreased by the chlorinated phenol fungicide.

6. In an aqueous alkaline adhesive dispersion of a finely divided proteinaceous adhesive material consisting essentially of soluble dried blood and soya flour in a ratio of from 2:3.7 to 4:1, containing a polychlorinated phenol fungicide in an amount equivalent to about 5% by weight of the dry proteinaceous material, said polychlorinated phenol reducing the viscosity of the said adhesive, a cobalt salt soluble in the mixture producing a concentration of cobalt ions raising the viscosity of the adhesive at least as much as it is decreased by the polychlorinated phenol fungicide.

7. In an aqueous alkaline adhesive dispersion of a finely divided proteinaceous adhesive material consisting essentially of soluble dried blood and soya flour in a ratio of from 2:3.7 to 4: 1, containing a pentachlorophenol fungicide in an amount equivalent to about 5% by weight of the dry proteinaceous material, said pentachlorophenol reducing the viscosity of the said adhesive, a cobalt salt soluble in the mixture producing a concentration of co balt ions raising the viscosity of the adhesive at least as much as it is decreased by the pentachlorophenol fungicide.

8. In an aqueous alkaline adhesive dispersion of a finely divided proteinaceous adhesive material consisting essentially of soluble dried blood and soya flour in a ratio of from 2:3.7 to 4: 1, containing a polychlorinated phenol fungicide in an amount equivalent to about 5% by weight of the dry proteinaceous material, said polychlorinated phenol reducing the viscosity of the said adhesive, a cobalt salt in an amount equivalent to about 0.1% to 0.5% by weight of the dry proteinaceous material where the cobalt salt is calculated on the anhydrous basis, said cobalt salt being soluble in the mixture and producing a concentration of cobalt ions raising the viscosity of the adhesive at least as much as it is decreased by the polychlorinated phenol fungicide.

9. In an aqueous alkaline adhesive dispersion of a finely divided proteinaceous adhesive material consisting essentially of soluble dried blood and soya flour in a ratio of from 2:3.7 to 4: 1, containing a pentachlorophenol fungicide in an amount equivalent to about 5% by weight of the dry proteinaceous material, said pentachlorophenol reducing the viscosity of the said adhesive, a cobalt salt in an amount equivalent to about 0.1% to about 0.5 by weight of the dry proteinaceous material where the cobalt salt is calculated on the anhydrous basis, said cobalt salt being soluble in the mixture and producing a concentration of cobalt ions raising the viscosity of the adhesive at least as much as it is decreased by the pentachlorophenol fungicide.

10. The method of fungicidally treating an aqueous alkaline adhesive dispersion of finely divided proteinaceous adhesive material consisting essentially of soluble dried blood, soya flour, and a polychlorinated phenol fungicide reducing the viscosity of the said adhesive, consisting essentially of raising the viscosity of the adhesive at least as much as it is decreased -by the polychlorinated phenol fungicide by adding a cobalt salt soluble in the mixture.

11. The subject matter of claim 10 in which said cobalt salt is added in an amount from about 0.1% to about 0.5% by weight of the dry proteinaceous material where the cobalt salt is calculated on the anhydrous basis.

12. The method of fungicidally treating an aqueous alkaline adhesive dispersion of finely divided proteinaceous adhesive material consisting essentially of soluble dried blood, soya flour in a ratio of 2:3.7 to 4:1, and a polychlorophenol viscosity decreasing fungicide in an amount equivalent to about 5% by weight of the dry proteinaceous material, consisting essentially of raising the viscosity of the adhesive at least as much as it is decreased by the polychlorophenol fungicide by adding a cobalt salt soluble in the dispersion.

13. The subject matter of the method of claim 12 in which the cobalt salt is added in an amount from about 0.1% to about 0.5% by weight of the dry proteinaceous material where the cobalt salt is calculated on the anhydrous basis.

14. Hot-press plywood glued with the fungicidally treated adhesive produced by the method of claim 10.

15. Hot-press plywood glued with the fungicidally treated adhesive produced by the method of claim 11.

16. Hot-press plywood glued with the fungicidally treated adhesive produced by the method of claim 12.

17. Hot-press plywood glued with the fungicidally treated adhesive produced by the method of claim 13.

18. A dry adhesive base material, consisting essentially of a mixture of soluble blood and soya flour in a ratio of from 2:3.7 to 4:1, and a soluble cobalt salt in an amount equivalent to about 0.1% to about 0.5% by weight of the dry proteinaceous mixture and dispersed therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 1,976,435 Cone et al Oct. 9, 1934 2,297,340 Wood Sept. 29, 1942 2,379,402 Scholz et a1. June 26, 1945 2,431,119 Horvath Nov. 18, 1947 2,433,783 Paterek Dec. 30, 1947 2,462,811 Konen et al Feb. 22, 1949 

1. IN AN AQUEOUS ALKALINE ADHESIVE DISPERSION OF A FINELY DIVIDED PROTEINACEOUS ADHESIVE MATERIAL CONSISTING ESSENTIALLY OF SOLUBLE DRIED BLOOD AND SOYA FLOUR IN A RATIO OF FROM 2:3.7 TO 4:1, CONTAINING A VISCOSITY DECREASING FUNGICIDE IN AN AMOUNT EQUIVALENT TO ABOUT 5% BY WEIGHT OF THE DRY PROTEINACEOUS MATERIAL, A COBALT SALT SOLUBLE IN THE MIXTURE PRODUCING A CONCENTRATION OF COBALT IONS RAISING THE VISCOSITY OF THE ADHESIVE AT LEAST AS MUCH AS IT ID DECREASED BY THE FUNGICIDE. 